3-way component system help

Hi,

I'm toying around with the idea of replacing my boston rally RC61's with a 3 way component system, such as a focal polyglass 165v3 or polykevlar 165k3 (although this last one is too expensive for me heh). I'm all for SQ. How much better is a 3-way system than a 2-way, SQ wise? Is it worth it changing my speakers? Lastly, what brands/models would you recommend? Thx.